import math

x1,y1,x2,y2 = map(float,raw_input().split())
a = math.sqrt((x1-x2)**2+(y1-y2)**2)
print '%f'%a import math math x1,y1,x2,y2 = map(float,raw_input().split()) x1 map(float,raw_input().split()) map float raw_input().split() ().split () raw_input split y1 x2 y2 a = math.sqrt((x1-x2)**2+(y1-y2)**2) a math.sqrt((x1-x2)**2+(y1-y2)**2) math.sqrt math sqrt (x1-x2)**2+(y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 print '%f'%a '%f' a x1,y1,x2,y2 = map(float,raw_input().split()) map(float,raw_input().split()) x1 y2 = map(float,raw_input().split()) map(float,raw_input().split()) y2 x2,y2 = map(float,raw_input().split()) map(float,raw_input().split()) x2 a = math.sqrt((x1-x2)**2+(y1-y2)**2) math.sqrt((x1-x2)**2+(y1-y2)**2) a y1,x2,y2 = map(float,raw_input().split()) map(float,raw_input().split()) y1
import math

x1,y1,x2,y2 = map(float,raw_input().split())
a = math.sqrt((x1-x2)**2+(y1-y2)**2)
print '%f'%a